In the Department of Veterans Affairs (VA), treatment for Veterans with musculoskeletal diagnoses (MSD), a cluster of disorders including back and neck problems, osteoarthritis, nerve compression, and other inflammatory and degenerative disorders, has long been managed in the primary care setting. This observation is consistent with the Stepped Care Model of Pain Management (SCM-PM) that is the VA's single standard for pain care and that asserts that most common pain conditions should be managed in the Primary Care setting by Patient Aligned Care Teams. Yet, little is known about the characteristics of Veterans with MSD, the development and persistence of pain, associations with medical and mental health comorbidities, variability in pain management, and outcomes and costs of various treatments. These data are needed in order to identify variation and gaps in pain care that can inform quality improvement efforts. For the proposed project, we will create a longitudinal cohort of Veterans with MSD in VA care using existing national VA electronic clinical and administrative data. These data will be used to characterize Veterans with MSD receiving VA care, and examine variation in pain, pain treatment, effects of comorbidities, and outcomes, including costs by patient and facility characteristics. Interpretation and use of the data will be informed by the Chronic Care Model which provides an overarching framework for this project. The MSD cohort will serve as a foundational Clinical Information System to understand and inform efforts to promote Delivery Systems and Health System Organizational Change consistent with ongoing VA transformational efforts to encourage Veteran- centered care and implementation of the SCM-PM. Our specific aims are to: 1) Identify Veterans with MSD and describe their socio-demographic and clinical characteristics, variation in pain screening, severity and persistence of pain; duration and recurrence of MSD episodes; 2) Assess variation in treatment and outcomes, including disparities in types of treatment (including opioids), and time to initiate treatment, by patient and facility characteristics; effect of mental health services on pain reports and comorbid depression; and adverse events, and their predictors, associated with chronic opioid therapy (COT); and 3) Estimate the costs of MSD care, by patient and facility characteristics, and by clinical characteristics (e.g., specific MSD, comorbidities, and duration), and resulting from adverse events associated with COT. Preliminary work by our experienced team of investigators from several VA HSR&D Centers, in addition to support from our patient care services and operations partners, will facilitate rapid creation of the full cohort. An early deliverable of this project will be a comprehensive database that can serve the analytic needs of these groups. The cohort is designed to inform other CREATE projects by providing validated algorithms to facilitate use of VA electronic health record data to identify health services utilization, presence of comorbid conditions, receipt of opioid medications, and pain screening results, among other dimensions of care, over time. We will share codes for constructing variables, or share data through merges with our existing datasets. The project will provide important data on pain management to directly support the strategic plan of the National Pain Management Program Office and our other partners. Of particular importance is the opportunity for this project to play a key role in the development of pain management performance measures for VHA through our collaboration with the Office of Analytics and Business Intelligence.